According to ESRB, this game contains: Violence
Parents should feel safe with Sub Rebellion. All combat is between vehicles or giant robots, so there is no explicit blood or gore. There is also no questionable language and no sexual content whatsoever unless you want to count a rather phallic-shaped missile that seems to propel itself by thrusting.
Shooter Fans should give the game a try. Its not exactly like an outer space or aerial shooter, but it has enough of the same basic energy combined with a uniqueness all its own to warrant making it part of your library.
Submarine Fans are in for a treat its not exactly everyday that a game featuring underwater action comes along, not to mention one as good as this. The graphics are smooth and attractive, the sonar feature is incredibly nifty and the option to surface makes it the total submarine package. As a side note, Irem also makes another submarine Shooter, although its 2D and for the PlayStation called In The Hunt. The gameplay is radically different, but its still great.
Hearing Impaired Gamers will have no problems here. All information is communicated via text and there are no significant auditory cues.